=over

=item tie VARIABLE,CLASSNAME,LIST

This function binds a variable to a package class that will provide the
implementation for the variable.  VARIABLE is the name of the variable
to be enchanted.  CLASSNAME is the name of a class implementing objects
of correct type.  Any additional arguments are passed to the "C<new()>"
method of the class (meaning C<TIESCALAR>, C<TIEARRAY>, or C<TIEHASH>).
Typically these are arguments such as might be passed to the C<dbm_open()>
function of C.  The object returned by the "C<new()>" method is also
returned by the C<tie()> function, which would be useful if you want to
access other methods in CLASSNAME.

Note that functions such as C<keys()> and C<values()> may return huge lists
when used on large objects, like DBM files.  You may prefer to use the
C<each()> function to iterate over such.  Example:

    # print out history file offsets
    use NDBM_File;
    tie(%HIST, 'NDBM_File', '/usr/lib/news/history', 1, 0);
    while (($key,$val) = each %HIST) {
	print $key, ' = ', unpack('L',$val), "\n";
    }
    untie(%HIST);

A class implementing a hash should have the following methods:

    TIEHASH classname, LIST
    DESTROY this
    FETCH this, key
    STORE this, key, value
    DELETE this, key
    EXISTS this, key
    FIRSTKEY this
    NEXTKEY this, lastkey

A class implementing an ordinary array should have the following methods:

    TIEARRAY classname, LIST
    DESTROY this
    FETCH this, key
    STORE this, key, value
    [others TBD]

A class implementing a scalar should have the following methods:

    TIESCALAR classname, LIST
    DESTROY this
    FETCH this,
    STORE this, value

Unlike C<dbmopen()>, the C<tie()> function will not use or require a module
for you--you need to do that explicitly yourself.  See L<DB_File>
or the F<Config> module for interesting C<tie()> implementations.

For further details see L<perltie>, L<tied VARIABLE>.

=back